In recent years, various means of effectively using a variety of energies have been considered in response to heightening environmental problems. In particular, accompanying the increase in industrial waste and the like, the effective utilization of waste heat generated during the incineration of these has become an issue. For example, waste heat recovery is performed in a large-scale waste incineration facility by generating high pressure steam from the waste heat, and generating electricity by causing a steam turbine to rotate by using this steam. However, in a medium-to-small scale waste incineration facility, which accounts for the large majority of waste incineration facilities, the amount of waste heat exhaust is small, and so the recovery method of generating electricity from the waste heat by way of a steam turbine or the like has not been feasible.
As an electricity generation method using waste heat that can be employed in such medium-to-small scale waste incineration facilities, for example, methods using thermoelectric conversion elements and thermoelectric conversion modules for reversibly performing thermoelectric conversion by utilizing the Seebeck effect or Peltier effect have been proposed.
The thermoelectric conversion element includes a thermoelectric conversion part, and a first electrode and a second electrode provided in the thermoelectric conversion part. The thermoelectric conversion part is a sintered body obtained by sintering a thermoelectric conversion material and cutting into a predetermined size. Meanwhile, the thermoelectric conversion module is a modularized thermoelectric conversion element. Bi—Te system, Pb—Te system, Si—Ge system, Fe—Si system, and Mg—Si system materials are known as the thermoelectric conversion materials. Among them, an Mg—Si system (based) thermoelectric conversion material is attracting attention as a thermoelectric conversion material having a small environmental load and being usable in a high temperature environment (Patent Documents 1 to 3, and the like).
Note that this thermoelectric conversion technology is applicable not only to the waste heat in waste incineration, but also waste heat discharged from various manufacturing factories, and various heats such as exhaust heat from automobiles, the heat of the earth, and solar heat.                Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2002-285274        Patent Document 2: Japanese Unexamined Patent Application, Publication No. 2006-128235        Patent Document 3: Japanese Unexamined Patent Application, Publication No. 2011-029632        